Ducting of rectangular and of circular sections has been used for many years in air-conditioning systems. Circular ducting has sometimes been made by a wrapping technique, in which a long length of sheet metal strip is wrapped around a subsequently withdrawn mandrel with successive turns in sealed overlapping relationship. More recently, an adaptation of this wrapping technique has made possible the production of modified rectangular ducting having rounded corners, so that two opposite sides of the ducting assume opposed approximate semi-circular configurations separated by the major dimension of the modified rectangular section. Ducting of this shape has some considerable advantages in practice, and is likely to be increasingly employed.
However, traditional and known methods of supporting air ducting are unsuitable or disadvantageous for modified rectangular ducting, and it is an object of the present invention to provide a supporting element for this ducting and a method of supporting such ducting using the supporting elements.